Magneto igniting device with revolving flux conductor



April l 1924.

f W. WALTHER MACNCTC ICNITINC DEVICE WITH REvoLvINC FLUX CONDUCTOR Filed Aug. 26 1919 Patented Apr. l, 1924.

UNITED STATES 1,488,722, PATENT; OFFICE.

WILHELM WALTHER, OF STUTTGART, GERMANY, ASSIGNOB T FIRM. 0I' `ROBEBY1T` BOSCH AKTIENGESELLSCHAFT, l0F STUTTGART, GEZRNILANY.` :y

MAGNETO' IGNITING DEVICE WITH BEVOLVING FLX Application inea mgm 2e, 191s. serial No. $26,069.

To all whom it may concern:

Be it known that I, WILHELM IALTHEB, a citizen of Germany, residing at and whose post olice address is Stuttgart, Kanonenweg g Devices with Revolving Flux Conducor; and I do hereby declare the followin yto be av full, clear, and exact description o e invention, such as will enable others skilled in the art to which it appertains to make and use the same.

It is known that the number of rises of potential occurring during one revolution in an ordina magneto electric i iting machine may e doubled if, instea of rotating the armature, a two-bar flux conductor be caused to revolve between a fixed armature and the pole pieces of the magnet of the machine. The device that regulates the flow of the magnetic lines of force through the iron core of the armature and from the one pole piece of the magnet to the other, takes the form of a cylindrical magnetizable shell that is slotted lengthwise So as to form a cage with a number of bars that actas flux conductors or flux directing members. These flux directing ca s have hitherto been used especially for eig t cylinder engines, because engines they may be driven at the with suc same speed as the crank shaft in order to a roduce the eight current impulses re uired 1 or the ignitions in two revolutions, 1. e. a

total working period of a four cycle engine. If these igniting machines are driven at of the speed of the crank shaft, the will also be specially4 suitable for hig speed six cylinder motors.

In newly-developed aeroplane en ines 12, 16 and even as many as 24 cylin ers, and. high speeds at that, are employed. The reviously mentioned cage type of ux con uctors are less suitable for these speeds, because they must be geared to rotate at high rates in order to obtain the large number of ignitions required in .a single working period of the pistons.

But it is desirable for durability and reliability of operation to keep the speed of revolution of the ignition machines as low as possible, so that with hig speed engines the ignition magneto shoul if possible, be driven at the same speed as the crank sha-ft or not more than 1% times as fast.

The object of the present invention is to 61, Germany, have .invented certain new` and useful Improvements in Magneto Ignitgive a means for producing a ylarge number of ignitions ata low ratio, of 'transiiiission.- y

The means devised `:for this purpose ac'- cording to this invention consists inA afmagneto-electric ignition generator in which therotating flux-conducting member or cage has more than two flux-conducting'y bars, andin which the distribution of the iron of the armature and of the two pole pieces 'ofthe' field magnet withrespect to the number and sizeof the said flux-'conducting lbars iss'u'ch that at each alternation of the voltagel .a change of the magnetic polarity ofthe arma-E ture iron takes ,f

The drawing lllustratesa number. of'fways of carrying outftheinvention.4 Fi y. l to 4 representsafgnitionm 'y to w ose flux-.conducting cagehas four-1 unl-.Q directin bars, .and Figs. 5 to 9k illustrate` modifie forms of the invention. In all ofthe figures a denotes the permanentfieldmagnets, b the pole pieces, and,`in 1604, c1c2c, c* ,the Aflux directing bars of the cage that 'rotates around the armaturefof double-T shape, d the fixed.- armature with its coil e, N the north Vole and S thesouthpole of the magnets. T e arrow indicates 4the'direction in which the cage rotates. l

In Fig. 1 the sition of the flux-directing bars issuch t at the lines of force emanating from. the north pole of the field magnet ass through the bar c1 into the upper sur ace of the armature core and out from the lower end of the armature through the bar c into the south pole as indicated by the arrows. In this osition of the cage the magnetic iiux throug the armature corev reachfs its highest value, whilst the induced volt e is zero. As the cage approaches the positlonshown in F ig. 2 the li'nes of force passing through the armature decrease. When the position indicated in Fi 2 l is reached, the lines of force pass rom the north pole through the flux-directing bars cl and ci to the south pole; the 100 magnetic fiux through the armature core sinks to its lowest value and then changes its direction, whereupon the induced voltage reaches its highest value, this maximum being utilized in the known manner for the 105 purpose of igniting. In the same measure in which the bars approach the position of Fig. 3 the number of lines of force, passing through the armature core and inducing a current, increase, but they now pass through 110 the armature core in an opposite direction. The induced voltage sinks to zero. In Fig. 4 the lines of force pass from the north pole through the fiuxdirecting bars, the armature pole pieces to the south pole, without passing through the armature core. Thus a maximum of voltage is again obtained as in the case of Fig. 2. The described process is repeated as often as a pair ot flux-conducting bars give rise to an alternation of the magnetic flux passing through the iron core of the armature. This device thus produces 8 maxima of volt-age during a single revolution, so that if a magneto generator of this kind is employed in conjunction with a 16 cylinder engine that requires 16 ignitions in two revolutions, it must be driven at the same speed as the crank shaft.

A somewhat modified' type of magneto is shown in Fig. 5 in which a two-bar cage or shell f7` that is coupled with the stationary armature, is interposed between the revolving four-bar cage and the two field pole pieces. By turning the cage f and the armature d in the direction of rotation of the cage 01, or in the opposite direction, an earlier or a later change of the direction of the lines of force in the armature, and thus an earlier or a later moment of ignition, is obtained.

Further modifications are shown in Figs. 6-9. Fig. 6 represents an` ignition machine with 3 flux-directing bars. Fig. 7 a machine with 5,Fig. 8 with 6, and Fig. 9 with 8 flux-directing bars; and the shapes of the two field pole pieces and of the amature re quired for these numbers of bars are also illustrated in these figures. From these it follows that in the case of an uneven number of flux-directing bals, an uneven distribution of the iron forming the two field pole pieces, is required. The air gaps between the edges of the field pole pieces of opposite signs7 and theA armature core, are located upon the sides of an angle (Figs. 6 and 7) that is determined by radii which pass through two fluxdirecting barsof the reatest possible an lai` distance from eaci other. The numr of maximum values of voltage obtained dur ing a single revolution is in each case twiceo the number of flux-directing bars.

I claim:

In a magneto-electric ignition apparatu the combination of a field magnet with pole shoes, a stationary double-T armature with useful current winding arranged on the armature bar, and a guide piece for the lines of foroe of more than two segments, said guide-piece rotating around the armature and conveyin y the lines of force from the magnet pole-s ioes to the armature, the stationary iron conveying the magnetic lines of force being so arranged that at a time only two segments of the rotary guide-piece transmit the flux through the iron core of the useful-current windmg.

In testimony whereof I affix my signature, in presence of two witnesses.

WILHELM WALTHER.

Witnesses:

ADoLr Lumens, HERMANN SCHNEIDER. 

